Scientists use sunlight to produce steam without boiling water
Steam can be used to power all sorts of things, and has for centuries. While using steam as a power source is relatively benign for the planet, the process of making steam it quite energy intensive.
In most cases, a fossil fuel like coal or gas is burned in order to heat water in a container. Lots of energy is wasted heating the container, just so the water inside will reach the boiling point, and then stay there to produce steam.
With all that work involved, it’s no wonder that other forms of power have usurped steam. Recently however, a team of scientists decided to see if they could improve on the process and give steam a second chance. Their research has produced positive results, including a revolutionary new way to use sunlight to produce steam and other vapors without heating an entire container of fluid to the boiling point.
The secret to producing steam without boiling water lies in nanotechnology. The report, recently published in the American Chemical Society (ACS) journal ACS Nano, explains that metalic nanoparticles illuminated by light can be brought to 212 degrees Fahrenheit, the boiling point of water, much faster than water. Steam then forms around the surface of each nanoparticle, and eventually, the vapor escapes from the particle, forming nanobubbles that float to the top of the surface and escape as water vapor or steam.
Because millions of these nanoparticles can be easily added to water (the’yre so small that 1,000 would fit across the width of a human hair) the development has major implications for industries that rely on steam.
"This research opens up a revolutionary new application of nanoparticles in solar energy. The authors show that sunlight can be used to create steam with virtually no wasteful heating of the surrounding liquid. The potential societal benefits are staggering," said Paul Weiss, Ph.D., editor-in-chief of ACS Nano.
"They include more energy-efficient distillation of alcohol, a new and highly practical strategy for desalination and water purification and compact solar-driven sources of steam for sterilization and sanitation in resource-poor locations."